Copy the contents of the unpaker into Data/packs in your clean version of RTW 1.5.
Run the .bat file and let run completely. this may take a while. After its done you'll see a new data folder in the packs directory.
CUT or MOVE (not copy) this new Data folder and paste it over the root Data folder allowing it to overwrite everything. NOTE: There should be no Data folder left in Packs.
Go back to the packs folder and rename all the pak files remaining (except the patch_0 and patch_1) You can just rename them with a couple of xx in the front ie sprites_1.pak rename to xxsprites_1.pak